A computer program
that calculates the trajectories of masses
moving under mutual gravitation
. Programs of this sort are used in astrophysics
to study the long-term evolution of collections of stars, like globular clusters
. They can also be used as an orrery
A (woefully incomplete) list of n-body simulators available for free download (or as Java applets):
- http://www.cyf-kr.edu.pl/ftp/simtel/simtel_astronmy.html (contains a bunch of other astronomy software too).